Gas Diluter Portable Gas Dilution System User s Manual

Transcription

1 Gas Diluter Portable Gas Dilution System User s Manual Defiant Technologies, Inc Vol.1

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3 Gas Diluter Portable Gas Dilution System User s Manual Defiant Technologies, Inc Vol.1

4 Gas Diluter User s Manual This page is intentionally left blank. 4

5 TABLE OF CONTENTS Gas Diluter User s Manual Section 1: Getting to Know the Gas Diluter Manual Overview Operations Overview... 7 Section 2: Components Instrument Components... 8 Section 3: Instrument Setup Opening Exhaust Outlet Connecting to a Gas Cylinder Connecting to a FROG-4000 TM Selecting Valve Positions Powering On Section 4: Diluting a Gas Dilution Spreadsheet Diluting a Gas Section 5: Troubleshooting Rotameter Settings Are Not Stable

6 Gas Diluter User s Manual SECTION 1: GETTING TO KNOW THE GAS DILUTER 1.1 Manual Overview The Gas Diluter uses a practical approach to dilute gas mixtures and delivers metered amounts of VOCs to calibrate a portable GC. This manual includes the following: An overview of the Gas Diluter components and features. Detailed procedures for using the Gas Diluter. Troubleshooting information. 6

7 Gas Diluter User s Manual 1.2 Operations Overview The Gas Diluter mixes scrubbed ambient air with a calibration gas enabling the end user to perform a mutli-point calibration on a portable GC. The Gas Diluter is designed to be used with the FROG-4000 or other gas chromatographs. The basic steps for operating the system are: 1. Connecting a gas cylinder (containing a known concentration of calibration gas) to the Gas Diluter. 2. Connecting a FROG to the Gas Diluter. 3. Calculating the gas settings based on the desired concentrations for the calibration. 4. Diluting the gas. 7

8 SECTION 2: COMPENENTS Gas Diluter User s Manual 2.1. Instrument Components Components Reference for Gas Diluter A. Dilution Flow Rotameter B. Calibration Gas Mix Flow Rotameter A B 8

9 Gas Diluter User s Manual 2.1: Instrument Components Components Reference for Gas Diluter C. Pump Power Button D. Power Supply Port E. 1/4 inch Ambient Air Inlet F. 1/4 inch Nitrogen Inlet G. 2 Way Select Valve for Dilution Gas Allows selection of ambient air or nitrogen as the dilution gas H. 1/4 inch Gas Mix Inlet I. 2 Way Select Valve for Mode Allows for selection of Flush Mode or Dilution Flow J. 1/4 inch Exhaust K. Diluted Calibration Gas Outlet (1/8 inch outlet with a 1/8 to 1/16 adapter) E F G D C K J I H 9

10 SECTION 3: INSTRUMENT SETUP Gas Diluter User s Manual There are several procedures necessary to setup the Gas Diluter for proper use. The following procedures prepare the instrument for use: : Opening Exhaust Outlet : Connecting to a Gas Cylinder : Connecting to a FROG-4000 TM : Selecting Valve Positions : Powering On 10

11 Section 3: Instrument Setup Gas Diluter User s Manual 3.1: Opening Exhaust Outlet Remove cap from exhaust outlet O O Figure 3.1-1: Removing Exhaust Cap Figure 3.1-2: Exhaust Cap Removed 11

12 Gas Diluter User s Manual Section 3: Instrument Setup 3.2: Connecting to a Gas Cylinder Remove cap from gas mix inlet. Figure 3.2-1: Removing Gas Mix Inlet Cap N Q Figure 3.2-2: Gas Mix Inlet Cap Removed Obtain a gas cylinder containing known concentrations of analytes to the gas diluter. Figure 3.2-3: Pressurized Gas Cylinder 12

13 Gas Diluter User s Manual 3.2 Connecting to a Gas Cylinder Use proper fittings to connect the gas cylinder to the gas diluter via the Gas Mix Inlet. Figure 3.2-4: Connecting the gas cylinder via the Gas Mix Inlet Figure 3.2-5: Gas Diluter with gas cylinder connected 13

14 Gas Diluter User s Manual Section 3: Instrument Setup 3.3: Connecting to a FROG-4000 TM The Gas Diluter is designed to easily connect to the FROG-4000 TM. However, it is possible to use the Gas Diluter with other gas chromatography systems. The Instructions that follow are for connecting the Gas Diluter to a FROG-4000 TM. Obtain a FROG with an air sampler connected. For more detail about air sampling consult the FROG-4000 User s Manual. Connect the air sampler transfer line that is included with the FROG-4000 s air sampler kit to the Calibration Gas Outlet. Figure 3.3-1: Attaching transfer line to Calibration Gas Outlet. Figure 3.3-2: Transfer line attached to Calibration Gas Outlet. 14

15 Gas Diluter User s Manual 3.3. Connecting to a FROG-4000 Make sure the transfer line is also attached to the FROG s air sampler box. Figure 3.3-3: Transfer line connecting FROG-4000 and Gas Diluter. 15

16 Gas Diluter User s Manual Section 3: Instrument Setup 3.4: Selecting Valve Positions The 2 Way Select Valves direct the flow of gas in the Gas Diluter. Having these valves in the correct position is important for successful use of the Gas Diluter. I G Figure 3.4-1: 2 Way Select Valves G. 2 Way Select Valve for Dilution Gas: Allows selection of ambient air or nitrogen as the dilution gas If using air as dilution gas have valve pointed towards the A (Figure 3.4-2). Figure 3.4-2: Valve position for air as dilution gas If using nitrogen as dilution gas (attached to the N2 position) have valve pointed away from the A (Figure 3.4-3). Figure 3.4-3: Valve position for nitrogen as dilution gas 16

17 Gas Diluter User s Manual 3.4. Selecting Valve Positions I. 2 Way Select Valve for Mode: Allows for selection of Flush Mode or Dilution Flow If using gas diluter for dilution of a gas mix, valve should point toward the A (Figure 3.4-4). Figure 3.4-4: Valve position for gas dilution If flushing the lines of the Gas Diluter to clean it, the valve should point away from the A (Figure 3.4-5). Figure 3.4-5: Valve position for air as dilution gas 17

18 Gas Diluter User s Manual Section 3: Instrument Setup 3.5: Powering On Connect power supply to outlet and to Gas Diluter. To turn on Gas Diluter, press power button once (Figure 3.5-2). To turn off Gas Diluter, press power button once. To Outlet To Gas Diluter Figure 3.5-1: Power Supply for Gas Diluter. Figure 3.5-2: Plugged in power supply, power button. 18

19 Gas Diluter User s Manual 3.4 Powering On The Gas Diluter is now setup and ready to use. The figure below shows what the Gas Diluter should look like at this stage (Figure 3.5-3). Figure 3.5-3: Gas Diluter ready to use. 19

20 SECTION 4: DILUTING A GAS Gas Diluter User s Manual 4.1: Dilution Spreadsheet Included with the Gas Diluter is a spreadsheet containing calibration data. This calibration data is important for calculating the final concentration of the gas exiting the Gas Diluter. The first time the Gas Diluter is used the pressure at the location of use needs to be set. On the settings and concentrations spreadsheet enter the pressure at the location the Gas Diluter is being used in mmhg (Figure 4.1-1). Pressure at Location of Use (mmhg): 740 Figure 4.1-1: Pressure Input on Settings and Concentrations Spreadsheet To calculate the final concentration of the calibration gas, adjust the settings of the gas mix flow and the dilution flow in the settings and concentrations spreadsheet (Figure 4.1-2). In the example in Figure the bottle concentration (gas mix) is 1000ppb. To dilute the gas mix to 100ppb, the dilution gas setting is 15 and the gas mix setting is 100. This calculation is shown below. Note that the flow rates have already been calculated and are included in the spreadsheet. Also note that the bottle concentration should be changed to the concentration of the gas mix entering the gas diluter. 20

21 Dilution Gas Gas Mix Setting Flowrate (ml/min) Setting Flowrate (ml/min) Bottle Conc (ppbv) Final Conc (ppbv) Figure 4.1-2: Example Table of Settings and Concentrations. Gas Diluter User s Manual 21

22 Gas Diluter User s Manual 4.1 Dilution Spreashsheet For ease of use, the settings columns can be edited in the spreadsheet to produce different concentrations. For example, if 150 ppb is desired rather than 100ppb, the dilution setting can be adjusted to 10 and the gas mix setting can be adjusted to 110 (Figure 4.1-3). The Columns in Figure and Figure that are highlighted in blue (Dilution Gas Setting, Gas Mix Setting and Bottle Concentration) are the columns to edit to adjust the settings and to account for the bottle concentration. The Final Concentration column, highlighted in yellow will provide the final concentration based on the settings and the bottle concentration. 22

23 Dilution Gas Gas Mix Setting Flowrate (ml/min) Setting Flowrate (ml/min) Bottle Conc (ppbv) Final Conc (ppbv) Figure 4.1-3: Example Table of Settings and Concentrations. Gas Diluter User s Manual 23

24 4 Diluting a Gas Gas Diluter User s Manual 4.2: Diluting a Gas This section describes the procedure for using the gas diluter to dilute a gas mix to a desired concentration for calibration. 1. After determining which concentrations are desired use the spreadsheet to determine what gas mix and calibration flow settings correspond to the desired concentrations. 2. Once the settings are known, turn the knobs at the bottoms of both the gas mix flow rotameter and the dilution flow rotameter to reach the desired settings (Figure 4.2-1). Figure 4.2-1: Adjusting the Gas Mix Flow Rotameter. 24

25 Gas Diluter User s Manual 4.2 Diluting a Gas 3. It may take several minutes for the rotameter to stabilize at a setting. It is recommended that the user wait at least 90 seconds after obtaining a stable reading before collecting the calibration gas for samples. 4. After 90 seconds has elapsed since the rotameter settings have stabilized, the FROG-4000 can be used to take a sample. Please refer to the FROG-4000 s User s Manual for more detail on starting an air sample. 5. Repeat steps 2-4 until all samples have been taken. 25

26 Gas Diluter User s Manual SECTION 5: TROUBLE SHOOTING 5.1: Rotameter settings are not stable The rotameters are quite sensitive and take time to stabilize. However if after several minutes the setting is not stable it may be due to the pressure of the gas mix. It is recommended that the gas mix entering the gas diluter does not exceed 25psi. 26

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